Motor rotor hub assembly



y 1937. R. A. SAND'BERG 2,081,603

MOTOR ROTOR HUB ASSEMBLY Filed July 1, 1935 ll 5- 2 l I 10' Ii 14 j 10 fr 16' i flay Q: z ayzdery.

Patented May 25, 1937 UNITED STATES PATENT OFFICE Oakes ProductsCorporation,

North Chicago,

111., a corporation of Michigan Application July 1, 1935, Serial No.29,261

3 Claims.

This invention relates to a motor rotor hub assembly of a type suitablefor use in connection with motors for electrical refrigerators and thelike, and to a method of manufacturing such assembly.

A motor rotor hub assembly of the type to which this invention pertainshas heretofore been made from steel bar stock by a relatively expensivemethod. I have now found that the cost of manufacturing motor rotor hubassemblies of this type can be considerably reduced by making theassembly in two parts, one from a stamped and drawn metal sheet and theother from bar stock, and then uniting the two parts by copper brazingin a reducing atmosphere, such as hydrogen or the like.

It is therefore an object of this invention to provide a motor rotor hubassembly that can be manufactured at lower cost than heretofore.

It is a further important object of this invention to provide a motorrotor hub assembly formed in two parts and then copper brazed togetherin a reducing atmosphere.

Other and further important objects of this invention will becomeapparent from the following description and appended claims.

On the drawing:

Figure l is a plan view of a finished motor rotor hub assembly.

Figure 2 is a longitudinal sectional view of the same at one stage ofits manufacture.

Figure 3 is an end elevational view of the assembly as shown in Fig. 2.

Figure 4 is a longitudinal sectional view taken substantially along theline IV-IV of Fig. 1 showing also the rotor core structure and afragment of the stator core structure in section.

As shown on the drawing:

The reference numeral It] indicates a metal sleeve comprising anelongated cylindrical body portion and a reduced neck portion llextending from one end thereof and joined thereto integrally by ashoulder l2. The member [0 may suitably be formed from sheet metal, suchas steel, by a series of stamping and drawing operations, as will bewell understood by one skilled in this art.

A hub I3 is formed from bar stock with a cylindrical outer surface l4and a tapered inner surface 15. One end of the hub I3 is flanged as atIt and a portion of the periphery adjacent the flange I6 is slightlylarger in diameter than the cylindrical portion M to provide a shoulderl1 adapted, when the hub I3 is inserted into the neck portion II to abutagainst the end of said neck H. The outside diameter of the cylindricalportion i4 is substantially the same as the inside diameter of the neckll so as to provide a close fit.

In assembled relation, the hub I3 is mounted upon a motor shaft 2|having a tapered end portion 22 adapted to be received by the taperedbore of said hub l3. The hub assembly is secured in place on said shaft2| by means of a nut 23 threaded on to the extended end of said shaft2i. A motor rotor lamination assembly 24 is mounted upon the sleeve I0,preferably by a pressed fit. Stator laminations 25 surround the motorrotor laminations 24 in slightly spaced relation thereto, in accordancewith usual motor construction.

As shown in Figs. 2 and 3, after the hub [3 has been inserted into theneck II, a turn of wire I8 is laid in the fillet 19 between the innerend of the neck I l and the cylindrical portion I4. The wire l8 may beformed of copper or brass or some other alloy of copper, but ispreferably formed of substantially pure copper. The assembled parts withthe wire IS in place are then placed in a reducing atmosphere, such ashydrogen or a mixture of hydrogen, carbon monoxide or other reducinggases, and heated to a temperature above the melting point of the copperor brass, say between 1800 and 2100 F. Under these conditions the wirel8 melts and fiows by capillarity between the inner surface of the neckH and the outer cylindrical periphery M, as indicated at 20 (Fig. 4).The film of brazing metal 20 is greatly exaggerated in thickness forpictorial purposes only, since actually there is close metal to metalcontact between the hub and neck portion and no continuous interveningfilm of the brazing metal.

The welded joint thus produced between the bushing and the neck of thesleeve is substantially as strong, or even stronger than the metalitself from which the sleeve and bushing are formed. The hub and sleevemay be made from any suitable ferrous alloy or steel. It is important inassembling the parts that the fit between the hub and the neck H be asclose as possible and that the end of the neck be pressed against theshoulder IT in order to insure a satisfactory weld.

It will be appreciated that the method described represents aconsiderable saving over the cost of manufacturing a similar motor rotorhub assembly from a single piece of bar stock, not only from the pointof view of time and labor saved but also because of the saving in metalstock.

I am aware that many changes may be made and numerous details ofconstruction may be varied through a wide range without departing fromthe principles of this invention, and I, therefore, do not purposelimiting the patent granted hereon otherwise than necessitated by theprior art.

I claim as my invention:

1. An assembly comprising an elongated cylindrical body portion having areduced neck extending from one end thereof, a hub member having acylindrical outer surface inserted in said neck, said hub member havingan annular shoulder engageable with the extremity of the neck forlimiting the relative position of the hub member in said neck, and saidhub member and body being brazed together by a continuous surface brazetherebetween and inside of said body portion.

2. A motor rotor hub assembly comprising a cylindrical metal body memberhaving a reduced cylindrical neck, a bushing brazed in said neck the hubmember into the neck, said hub member projecting into the interior ofsaid stamping when positioned in said neck, and said hub member beingbrazed to said neck by a continuous sur face braze between the hubmember and the inner end of the neck, said braze constituting the soleconnection between said stamping and hub member for preventing relativemovement between them.

RAY A. SANDBERG.

